Many organic and inorganic reactions can be accelerated if the reaction occurs at an elevated temperature or pressure, or both. Pressure and temperature reaction vessels, commonly referred to as "bombs," have been developed for this purpose. Such bombs are also known as "decomposition vessels," "reduction bombs," and "pressure bombs." Such bombs typically comprise a containment vessel manufactured from stainless steel or other corrosion-resistant alloys. The vessel defines a reaction chamber which is sealable with a lid.
To cause or accelerate a reaction, reactants are introduced into the vessel and the lid sealed. The vessel is then heated in a variety of ways. Vessels are typically heated by convection in ovens, or conduction in water baths, sand baths, oil baths, mantels, or block heaters. In all cases, heat is externally generated and transferred to the vessel by conduction or convection. The reactants are thus heated by conduction through the vessel walls.
It is relatively important that the pressure and temperature limits of the bomb not be exceeded. For bombs of this type, it is relatively simple to determine the pressure which exists in the bomb because bomb pressures are ordinarily a function of the reactant temperature and any exothermic reaction which may be occurring inside the bomb. In the absence of an exothermic reaction, the bomb temperature is always less than or equal to the temperature of the oven or other device which is used to heat the bomb. The partial pressure of gases developed within the bomb must be estimated.
While such bombs have been advantageously used in research and in industry, a number of disadvantages are associated with these bombs. The, cycling of reactions through various heating stages is slow, as it is often necessary to allow the bomb to cool (i.e., to add another reactant, etc.) before a subsequent heating can commence. Substantial amounts of energy are wasted in convection heating. The rate of energy transfer by conduction and convection is relatively slow. Using convection heating, it typically takes 2 hours for the bomb to reach a desired temperature of 200.degree.-250.degree. C. Subsequent cooling of the bomb to handling temperature takes a corresponding time period. Thus, cycle periods of 4 hours are not uncommon.
A microwave-transmissible reaction vessel consisting essentially of a microwave-transmissible cup with a screw-on cap is available to provide rapid heating of reactants by exposure to microwaves. This reaction vessel is disadvantageously incapable of withstanding substantially elevated internal pressures. Furthermore, this vessel does not provide for the safe relief of internal pressure should an over-pressure condition occur nor for indication of pressure achieved in the vessel.